1. Field of the Invention
The present invention relates to methods and arrangements for controlling brightness, contrast and/or backlighting levels of camera image displays, in particular, methods and arrangements for controlling brightness, contrast and/or backlighting levels of camera image displays without the use of ambient light sensors.
2. Related Art
Conventional silver halide and digital cameras that employ the use of electric viewfinders to display images require the use of ambient light sensors to control the brightness, contrast and/or backlighting levels of the viewfinders. These viewfinders are often of the liquid crystal display (LCD) type. For example, when LCDs are viewed at certain ambient brightness levels, these displays may be difficult to read. Therefore, ambient light sensors are used to control the amount of backlighting and/or contrast applied to the display in order to make them easier to view.
Normally, such an ambient light sensor is mounted next to the LCD and detects the amount of ambient light that strikes thereon. Alternatively, the sensor may be located somewhere other than next to the LCD, but it should be in the vicinity of the LCD. Upon detection of an ambient lighting situation that may cause difficult viewing of the LCD, the ambient light sensor sends instructions to a controlling mechanism that adjusts the brightness, contrast and/or backlighting levels accordingly for easier viewing of the LCD.
Manual adjustment of LCDs is also used to compensate the brightness, contrast and/or backlighting levels. Such manual adjustment is done using a dedicated adjustment knob or through a xe2x80x9csoftxe2x80x9d adjustment accessed though the camera""s graphical user interface (GUI).
A method and arrangement have been created that eliminate the use of ambient light sensors and manual adjustors to control the brightness, contrast and/or backlighting levels of LCDs employed on cameras. In particular, using existing components of conventional digital cameras it is possible to make adjustments in the brightness, contrast and/or backlighting levels of camera LCDs.
Specifically, the camera""s exposure information is obtained using built-in auto-exposure algorithms in order to determine a scene""s brightness level. This brightness level is then used as an approximation for the ambient brightness level. For most picture-taking situations, this is a reasonable approximation. Then, using the determined level, an empirically determined table of known brightness values that are associated with typical ambient lighting conditions is referenced. Using the known brightness values as a reference, the brightness, contrast and/or backlighting levels of the LCD are controlled.
Additional features and advantages of the invention will be more fully apparent from the following detailed description of the preferred embodiments, the appended claims and the accompanying drawings.